Creators of Apple Watch apps keep It simple

Developers creating apps for the Apple Watch are learning a valuable lesson: less is more.

For smartphones including Apple Inc. ’s iPhone, developers streamlined websites and software designed for personal computers to adapt to the phones’ smaller display and touch screen. The Apple Watch is forcing them to think even smaller.

Creators of Apple Watch apps plan to offer quick nuggets of information or brief interactions based on a single tap. They’re placing a premium on immediacy and relevancy—often based on location—to anticipate a user’s needs. They don’t anticipate long sessions with their apps, but aim for a “get in and get out” experience.

“If people use their desktop computers for hours at a time and their phones for minutes at a time, we think people will use the Watch for seconds at a time,” said Shayne Sweeney, an engineering manager at Facebook Inc. ’s photo-sharing site Instagram, which created a Watch app.

Apple starts accepting orders on Friday for the Watch, its first all-new product since the iPad in 2010. It goes on sale April 24.

Apple hopes to repeat history by coming late to a new category of hardware—as it did with the iPod music player and iPad tablet computer—and defining the space by making its product smarter and more useful.

Samsung Electronics Co. , Sony Corp. and others have released smartwatches, but sales have been sluggish in part because consumers struggled to find a reason to buy another device. Apple is betting that outside developers can create compelling and useful experiences to push its Watch into the mainstream.

“The reason why you’d want [an Apple] Watch isn’t the same for everyone,” said Jan Dawson, chief analyst at Jackdaw Research, a consumer-technology research and consulting firm. “Apple is checking some of the big boxes that are broadly relevant. But the third-party developers will check all the other boxes.”

Apple has hosted meetings for hundreds of app makers in recent months to help them create enticing Watch apps.

In a letter to employees earlier this week, Apple Chief Executive Tim Cook said more than 1,000 Watch apps had been submitted since Apple started accepting applications last week. By comparison, Apple said there were 3,000 apps optimized for the iPad when it launched in 2010. The iPhone initially didn’t offer apps, because then-CEO Steve Jobs worried they would compromise the experience. When Apple opened its App Store in 2008, it started with 500 apps.

Google Inc. said there are “thousands of apps” compatible with its Android Wear software, released last year for rival smartwatches.

The smaller screen is a crucial challenge for Watch app developers. Apple Watch screens are less than half the size of the smallest four-inch iPhone display.

But Apple gave developers a new tool not available on the iPhone: Notifications can be more than text, and include photos or charts.

For its Watch app, Instagram initially considered including features from its smartphone app, such as discovering or searching for photos. But it found such features were too complicated for a smaller screen. Instead, it created notifications that can include photos, Mr. Sweeney said.

From a notification, a user can “like” a photo immediately or comment with special “emoji” icons created by Instagram. To type a comment or search for a hashtag, users need to switch to an iPhone. The Apple Watch works together with the iPhone; apps run on the phone and are displayed on the wrist.

Adam Grossman, founder of Dark Sky, a popular weather app for the iPhone and, soon, the Apple Watch, said notifications will in some cases take the place of the app, and help developers keep interactions brief. “Who wants to keep their wrists up to their face for many minutes?” he asked.

Travel site Expedia Inc. said such short interactions shift user expectations of how to get information. Instead of “pulling” information from websites or apps, users will want relevant information “pushed” to them at the most useful moments.

For a single trip, the Expedia Watch app has more than 20 itinerary-focused notifications, said John Kim, Expedia’s chief product officer. On the way to the airport, for instance, the Watch app can notify users of the proper terminal and whether a flight is on time. In the airport, notifications may include a reservation-confirmation number or gate assignment. On arrival, users will be notified of the location of baggage claim, the rental car or the hotel address.

“We have to anticipate things and use events as triggers to know what type of content we want to get in front of you,” said Mr. Kim.

Expedia said it will monitor how users react to notifications to see which ones are useful and which are a nuisance. Users can always opt out of notifications.

American Airlines said its Watch App also focuses on the “travel day” experience with features like a countdown to departure time or a seat assignment. But it omitted a key aspect of its smartphone app: the ability to book flights.

“We don’t expect folks to go through a five-minute booking process,” said Kevin MacFarland, who led the airline’s Watch app development team. “The goal is the right information at the right time.”